“Anxiolytic” action of diazepam and abecarnil in a modified open field test

The effects of acutely administered diazepam and the β-carboline abecarnil were examined in two animal models of anxiety in rats, and for their effects on food intake and locomotor activity. In the elevated x-maze diazepam (0.6–2.5 mg/kg) and abecarnil (0.03–0.3 mg/kg) induced anxiolytic-like effects. The second paradigm is based upon the suppression of feeding by exposure to a novel environment, adapted from Bodnoff et al. (1989). Food-deprived rats were placed in a corner of the open field containing food in the centre. The number of rats beginning to eat in the first 5 min was recorded. Diazepam (2.5–5.0 mg/kg) and abecarnil (0.01–0.3 mg/kg) increased the number of rats eating. Flumazenil, the benzodiazepine antagonist, was without effect, but antagonised the effects of diazepam and abecarnil. In a seperate series of experiments the effects of diazepam and abecarnil on feeding and locomotor activity were excluded as having influenced the the anxiolytic effects of these compounds in the animal models of anxiety.